Essay on Pinhole Optics

1990 Words Mar 25th, 2015 8 Pages
Fall 2005

Purpose: To learn how a pinhole affects how we see things using a pinhole magnifier and pinhole camera.

I. Introduction

A pinhole is exactly what it sounds like, a small hole made with a pin. Experiments with pinholes are useful because the way light travels through the hole is very similar to the way light travels through the eye. The pupil, the small black area in the center of the eye, acts similarly to the pinhole. It is small compared to the big things in the world you are looking at. The retina, the back part of the eye where special cells sense light and send signals to the brain via nerves, acts similarly to
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Unfortunately, there is a trade-off between the resolution, or sharpness, of the image and its brightness. A tiny pinhole produces a very sharp image, but since it decreases the number of rays that enter your eye, the pinhole makes the object look much dimmer.

By using a pinhole magnifier, nearsighted people who normally see things fuzzily at a distance will be able to see them clearly; likewise, farsighted people who normally see things fuzzily close up will be able to see them clearly.

Try it! If you or any of the students wear glasses, remove them before looking through the magnifier.

III. Pinhole Cameras
1 Sample pinhole camera
20 Pringles cans with lid cut into 2 pieces
20 Pieces of Aluminum foil ~1’ square (wrapped around paper towel roll)
8 Rolls of scotch tape (in a Ziploc bag)
20 Thumb tacks (in a jar)

• Organize students into 8 groups. • Give each group: a roll of tape • Give each student: a large and small piece of a Pringles can with the lid, a piece of aluminum foil that is approximately 1’ square, and a thumb tack. • The Pringles can has already been cut so there is one long piece, with the lid on top, and one small piece about 2” long. • Show students the sample pinhole camera to give them an idea of what they are creating.

Students then: • Use the thumb tack to make a hole in the center of the metal bottom. • Put the plastic lid on the cut end

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